A tool machine, particularly an air tool, drives and rotates a grinding assembly by an air pressure so as to grind an object.
In a conventional air tool machine, in order to allow an air pressure to pass through, an air channel allowing a gas to pass through is usually provided in advance on an angle-type air tool housing, so as to drive the grinding assembly.
As previously described, the air channel on the angle-type air tool machine is a curved channel instead of a linear channel, such that an associated manufacturing process suffers from various limitations.
A current angle-type air tool housing is primarily manufactured through casting, particularly through sand mold casting. When sand mold casting is adopted, a sand core is removed, and the air channel is then formed in the angle-type air tool housing.
However, the manufacturing method using casting is both high in cost and slow in production efficiency, and the angle-type air tool housing formed also has a heavy weight. For an operator that needs to hold the air tool machine for an extended period of time, such air tool machine is strenuous and may further cause occupational injuries over an extend period of use.